The antigenic determinants of lysozyme will be delineated. Lysozyme will be cleaved enzymically and chemically to yield fragments with intact disulfide bonds. The peptides will be tested for their inhibitory activity of lysozyme-antilysozyme system. Immunochemically active peptides will be purified, characterized and studied for their binding by equilibrium dialysis. Antibodies against pure peptides will be prepared and studied for their inhibition of enzymic activity of lysozyme. The relative amount of antibodies against the different antigenic determinants in sera of a given animal at different times during immunization and in different animals will be quantitated. This will shed some light on the antigenic determinants in terms of their relative immunodominancy. Also the immunochemistry of lysozyme derivatives will be studied, which are chemically modified at amino acid sites that have not yet been investigated. Conformational alterations resulting from the modification will be determined. BIBLIOGRAPHIC REFERENCES: Atassi, M. Z., Lee, C.-L. and Habeeb, A. F. S. A., Enzymic and immunochemical properties of lysozyme. XII. Delineation of the reactive site around the two central disulfides by immunochemical and conformational studies of derivatives of the two disulfide peptide. Immunochemistry 13:7 (1976). Atassi, M. Z., Koketsu, J. and Habeeb, A. F. S. A., Enzymic and immunochemical properties of lysozyme. XIII. Accurate delineation of the reactive site around the disulfide 6-127 by immunochemical study of beta-propiolactone lysozyme derivative and of synthetic disulfide peptides. Biochem. Biophys. Acta 420:358 (1976).